Characteristics of 3D TEM response on seafloor with the central loop configuration
Zhao Yue1, Xu Feng1, Li Xiu2, Liu Jinpeng2
1. Institute of Acoustics, Chinese Academy of Sciences, Beijing 100091, China; 2. College of Geology Engineering and Geomatics, Chang'an University, Xi'an, Shaanxi 710054, China
Abstract：This paper shows first our research on transient electromagnetic response characteristics in seafloor,i.e.how the seawater depth,the configuration size and the seafloor conductivity affect TEM response and its resolution.Then,the vector finite element method is used to perform 3D marine mode-ling with the central loop configuration,and the result is verified by 1D analytic solutions.Finally,3D models are designed respectively according to a real deep sea marine mineral exploration and a shallow sea engineering scenario,and the modeling results with 3D vector finite element method agree well with the real models.The modeling results indicate clear boundary of targets.So it is concluded that the central loop TEM method has an acceptable resolution for marine exploration.The work provides a valuable theoretical basis for the optimization exploration design and data processing and interpretation.
赵越, 许枫, 李貅, 刘金鹏. 中心回线海底三维瞬变电磁响应规律分析[J]. 石油地球物理勘探, 2017, 52(5): 1093-1102.
Zhao Yue, Xu Feng, Li Xiu, Liu Jinpeng. Characteristics of 3D TEM response on seafloor with the central loop configuration. OGP, 2017, 52(5): 1093-1102.
何继善,鲍力知.海洋电磁法研究的现状和进展.地球物理学进展,1999,14(1):7-39.He Jishan,Bao Lizhi.The situation and progress of marine electromagnetic method research.Progress in Geophysics,1999,14(1):7-39.
[2]
何展翔,孙卫斌,孔繁恕等.海洋电磁法.石油地球物理勘探,2006,41(4):451-457.He Zhanxiang,Sun Weibin,Kong Fanshu et al.Marine electromagnetic approach.OGP,2006,41(4):451-457.
Constable S.Ten years of marine CSEM for hydrocarbon exploration.Geophysics,2010,75(5):A67-A81.
[5]
刘颖,李予国.层状各向异性介质中任意取向电偶源的海洋电磁响应.石油地球物理勘探,2015,50(4):755-765.Liu Ying,Li Yuguo.Marine controlled-source electromagnetic fields of an arbitrary electric dipole over a layered anisotropic medium.OGP,2015,50(4):755-765.
[6]
Edwards R and Chave A.A transient electric dipole-dipole method for mapping the conductivity of the sea floor.Geophysics,1986,51(4):984-987.
[7]
Cheesman S J,Edwards R N,Chave A D.On the theory of sea-floor conductivity mapping using transient electromagnetic systems.Geophysics,1987,52(2):204-217.
[8]
Everett M E and Edwards R N.Transient marine electromagnetics:the 2.5-D forward problem.Geophysical Journal International,1993,113(3):545-561.
[9]
Weiss C J.The fallacy of the "shallow-water prob-lem" in marine CSEM exploration.Geophysics,2007,72(6):A93-A97.
[10]
李予国,Steven Constable.浅水区的瞬变电磁法:一维数值模拟结果分析.地球物理学报,2010,53(3):737-742.Li Yuguo and Constable S.Transient electromagnetic in shallow water:insights from 1D modeling.Chinese Journal of Geophysics,2010,53(3):737-742.
[11]
Barsukov P O and Fainberg E B.Transient marine electromagnetics in shallow water:A sensitivity and resolution study of the vertical electric field at short ranges.Geophysics,2014,79(1):E39-E49.
[12]
周建美,李貅,戚志鹏.浅水域各向异性地层中的瞬变电磁响应分析.石油地球物理勘探,2016,51(4):821-830.Zhou Jianmei,Li Xiu and Qi Zhipeng.Transient electromagnetic response analysis for anisotropic media in shallow water.OGP,2016,51(4):821-830.
[13]
刘长胜,林君.海底表面磁源瞬变响应建模及海水影响分析.地球物理学报,2006,49(6):1891-1898.Liu Changsheng,Lin Jun.Transient electromagnetic response modeling of magnetic source on seafloor and the analysis of seawater effect.Chinese Journal of Geo-physics,2006,49(6):1891-1898.
[14]
周逢道,林君,刘长胜等.中心回线关断时间对海洋电磁响应影响研究.电波科学学报,2012,27(1):203-207.Zhou Fengdao,Lin Jun,Liu Changsheng et al.Influence of the turn-off time with central loop device on its marine electromagnetic response.Chinese Journal of Radio Science,2012,27(1):203-207.
[15]
李慧,林君,王艳等.海底瞬变电磁探测技术的装置参数研究及实验.电波科学学报,2006,21(5):659-665.Li Hui,Lin Jun,Wang Yan et al.Equipment parameters and experiment of sea floor transient electromagnetic method.Chinese Journal of Radio Science,2006,21(5):659-665.
[16]
Swidinsky A,Hölz S,Jegen M.On mapping seafloor mineral deposits with central loop transient electromagnetics.Geophysics,2012,77(3):E171-E184.
[17]
Swidinsky A,Hölz S,Jegen M.Rapid resistivity imaging for marine controlled-source electromagnetic surveys with two transmitter polarizations:An application to the North Alex mud volcano,West Nile Delta.Geophysics,2015,80(2):E97-E110.
[18]
Jang H,Kim H J.Mapping deep-sea hydrothermal deposits with an in-loop transient electromagnetic me-thod:Insights from 1D forward and inverse modeling.Journal of Applied Geophysics,2015,123(12):170-176.
[19]
Nakayama K,Saito A.Development of new marine TDEM systems for the ocean bottom hydrothermal deposits.SEG Technical Program Expanded Abstracts,2014,33:850-854.
[20]
李丽,席振铢,王鹤等.海底钴结壳TEM的响应规律.工程地球物理学报,2015,12(3):283-293.Li Li,Xi Zhenzhu,Wang He et al.The TEM response of ocean cobalt crust.Chinese Journal of Engineering Geophysics,2015,12(3):283-293.
[21]
李貅.瞬变电磁测深的理论与应用.陕西西安:陕西科学技术出版社,2002,1-4.
[22]
Maaø F A.Fast finite-difference time-domain modeling for marine-subsurface electromagnetic problems.Geophysics,2007,72(2):A19-A23.
[23]
Singer B S.Electromagnetic integral equation approach based on contraction operator and solution optimization in Krylov subspace.Geophysical Journal International,2008,175(3):857-884.
[24]
Mulder W A,Wirianto M,Slob E C.Time-domain modeling of electromagnetic diffusion with a frequency-domain code.Geophysics,2008,73(1):F1-F8.
[25]
Marinenko A V,Epov M I,Shurina E P.Modeling electromagnetic field in shelf areas.Russian Geology and Geophysics,2009,50(5):475-484.
[26]
Um E S,Harris J M,Alumbaugh D L.3D time-domain simulation of electromagnetic diffusion pheno-mena:A finite-element electric-field approach.Geophy-sics,2010,75(4):F115-F126.
[27]
Um E S,Harris J M,Alumbaugh D L.An iterative finite element time-domain method for simulating three-dimensional electromagnetic diffusion in earth.Geophysical Journal International,2012,190(2):871-886.
[28]
Zaslavsky M,Druskin V,Knizhnerman L.Solution of 3D time-domain electromagnetic problems using optimal subspace projection.Geophysics,2011,76(6):F339-F351.
[29]
杨军,刘颖,吴小平.海洋可控源电磁三维非结构矢量有限元数值模拟.地球物理学报,2015,58(8):2827-2838.Yang Jun,Liu Yin,Wu Xiaoping.3D simulation of marine CSEM using vector finite element method on unstructured grids.Chinese Journal of Geophysics,2015,58(8):2827-2838.
[30]
Nabighian M N.Electromagnetic Methods in Applied Geophysics:Theory(Volume 1).SEG,1988,217-221.
[31]
Guptasarma D and Singh B.New digital linear filters for Hankel J0 and Jl transforms.Geophysical Prospecting,2010,45(5):745-762.
[32]
智庆全.MTEM波场变换与偏移成像方法研究[学位论文].陕西西安:长安大学,2015.
[33]
李建慧,朱自强,鲁光银等.回线源瞬变电磁法的三维正演研究.地球物理学进展,2013,28(2):754-765.Li Jianhui,Zhu Ziqiang,Lu Guangyin et al.Study on three-dimensional forward of transient electromagne-tic method excited by loop source.Progress in Geophysics,2013,28(2):754-765.
[34]
刘长胜,林君,周逢道.中心回线装置在海底的瞬变响应特征研究.电波科学学报,2010,25(1):195-200.Liu Changsheng,Lin Jun,Zhou Fengdao.Transient response characteristics of central loop configuration on seafloor.Chinese Journal of Radio Science,2010,25(1):195-200.
[35]
赵越,李貅,王祎鹏.大回线源瞬变电磁全域视电阻率定义.地球物理学进展,2015,30(4):1856-1863.Zhao Yue,Li Xiu,Wang Yipeng.Full-domain appa-rent resistivity definition for large-loop TEM.Pro-gress in Geophysics,2015,30(4):1856-1863.
[36]
Rona P A.Resources of the sea floor.Science,2003,299(5607):673-674.
[37]
朱克超,任江波,王海峰等.太平洋中部富REY深海粘土的地球化学特征及REY富集机制.地球科学,2015,40(6):1052-1060.Zhu Kechao,Ren Jiangbo,Wang Haifeng et al.Enrichment mechanism of REY and geochemical characteristics of REY-rich clay from the central Pacific.Earth Science,2015,40(6):1052-1060.
[38]
席振铢,李瑞雪,宋刚等.深海热液金属硫化物矿电性结构.地球科学,2016,41(8):1396-1401.Xi Zhenzhu,Li Ruixue,Song Gang et al.Electrical structure of sea-floor hydrothermal sulfide deposits.Earth Science,2016,41(8):1396-1401.
